Add a NULL check in strtol.

The spec says this is undefined behavior, but it will fix one more
problem with #8297

Change-Id: Ibc15f306c92b05019de1050a9eb239ba57b1a91e
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3029
Reviewed-by: Axel Dörfler <[email protected]>

src/system/libroot/posix/glibc/stdlib/strtod.c

@@ -494,6 +494,12 @@ INTERNAL (STRTOF) (nptr, endptr, group LOCALE_PARAM)
   struct locale_data *current = loc->__locales[LC_NUMERIC];
 #endif
 
+  if (nptr == NULL)
+  {
+      __set_errno (EINVAL);
+      return NAN;
+  }
+
   if (group)
     {
       grouping = _NL_CURRENT (LC_NUMERIC, GROUPING);

src/system/libroot/posix/glibc/stdlib/strtol.c

@@ -288,7 +288,7 @@ INTERNAL (strtol) (nptr, endptr, base, group LOCALE_PARAM)
     grouping = NULL;
 #endif
 
-  if (base < 0 || base == 1 || base > 36)
+  if (base < 0 || base == 1 || base > 36 || nptr == NULL)
     {
       __set_errno (EINVAL);
       return 0;